Hypoxia
Training
Early in May, a colleague and I flew to Renton (KRNT) in order
to experience the FAA’s portable reduced oxygen training enclosure (PROTE). This
chamber is capable of producing hypoxic environments at
ground level by altering the fraction of ambient oxygen. This avoids some of
the risks associated with pressurized altitude chamber training. The
purpose of the chamber is to learn how you will react when experiencing hypoxia
and to learn some of the signs associated with hypoxia. The chamber let us
experience what it would be like at 27,000’ without supplemental oxygen for
five minutes.
The
Flight
We had been watching the weather for a week leading
up to the flight and the extended forecasts would alternate back and forth
between VFR, MVFR, IFR. Making the flight under IFR conditions wasn’t the
issue, but there was a cold air system coming and the freezing levels were
forecast to be at 6000’ which is the typical north bound altitude assigned
between Portland and Olympia.
On the day of the flight the conditions enroute were
reported as VFR with rain showers along the route, so we expected we’d have to
deviate around and under areas of lower clouds and rain. We departed KSLE VFR
and encountered our first area of rain and low visibility near KHIO, but we
were easily able to deviate around the spots of weather and as we approached
KSPB there was some precipitation and spotty MVFR conditions ahead. As we
neared Kelso (KKLS) the ceilings started to drop and the visibility was
decreasing from VFR to MVFR. After a short time of being in low visibility we
decided that we needed an IFR clearance in order continue the flight.
While I looked up the ATC frequency for getting a
clearance, the pilot flying made a 180 degree turn back to the VFR conditions that we had
previously come from while I negotiated an IFR clearance to KRNT with ATC. Since
we didn’t have an IFR flight plan filed in the ATC system it some back and
forth between the controller to get all the relevant details of the requested
clearance, like aircraft type, equipment (/G, /A, etc.), desired route (in our
case direct OLM and then KRNT. But once the controller established radar
contact with our aircraft he asked us to assume our own terrain clearance until
reaching 4000’ before proceeding on course to OLM. For the remainder of the
flight he flew the airplane while I handled communication duties with ATC.
Our assigned altitude was 6000’ (remember earlier I
mentioned the freezing levels were 6000’)? As we settled in at altitude we were
closely monitoring the outside air temperature and watching to make sure that
any visible water droplets were moving across the airplane structure and not
becoming stationary (freezing). Sure enough, after a short time at 6000’ ice
started to form on the wing strut and the leading edge of the wing. Though it
was very light ice accumulation, we immediately reported the ice to ATC and
requested a lower altitude. We were assigned a new altitude of 5000’ and after
descending, the OAT increased to +2 degrees C and the water on the airplane
surfaces was moving again.
Once reaching OLM we were switched to Seattle
approach and began receiving vectors to the north west of Seattle in
preparation for the GPS 16Z approach at KRNT. Overall the flight from KSLE to
KRNT took about an hour and a half and about one hour of that was in instrument
meteorological conditions (IMC).
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| GPS 16Z |
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| Landing 16 |
Hypoxia Training
The chamber holds six people and before each group went in, we
were briefed as to what to expect and how to operate our pulse oximeter and
demand flow oxygen mask. We were given a clip board with some check boxes that
we were supposed mark when we experienced symptoms of hypoxia and some sample
math problems to work while in the chamber. Once in the chamber, the instructor would ask
random questions, like “if you burned 10 gallons an hour how many gallons you
would use…”. He would pick on individuals that appeared to be out of it do to
hypoxia. In fact, a few participants’ heads went limp and the instructor had to
put their mask on them. The point of the training wasn’t to see how long you
could go without oxygen, but to demonstrate to yourself what your hypoxic
limits were and the symptoms that you experience when at high altitudes.
As for me, I made it about 2 ½ minutes before feeling too dizzy and nauseous to
continue, so I donned the oxygen mask and recovered. my colleague went the full five minutes without
putting on the oxygen mask.
The Return
Flight
After the training, it was time for lunch before flying back to
KSLE so we took the opportunity to fly to one of my favorite dining spots,
Mukilteo Coffee Roasters on Whidbey Island, which is adjacent to W10. W10 is
located on the southern end of Whidbey Island and is a 20-minute flight from
KRNT. The airport is surrounded by trees and has a 2500’ runway, and the café
is a short walk up a path from the runway. After lunch we headed for home and
were able to make the entire return flight in VFR conditions.
